The preparation of espresso coffee involves the expression of heated water under pressure through a compressed portion of coffee grounds in order to deliver the desired serving of concentrated espresso coffee. It is known that in order to prepare a desirably high quality espresso coffee end product, the process by which the espresso is made must be carefully controlled. The variables involved in the production of espresso coffee that are known to have a significant effect on the quality of the espresso and which may be desirably controlled to result in a preferred high quality espresso coffee product include the volume of the espresso shot, the water temperature and pressure, the coffee grind dimensions, uniformity of grind dimensions, and quantity of coffee grounds used, and the degree of compression and surface characteristics of the coffee grounds through which the hot, high-pressure water is forced. As each of these variables affect the quality of the espresso coffee produced, it is desirable to be able to simply control each during the espresso-making process. Using commercially available espresso-making equipment, the only variables that are not simply controlled so as to be repeatable in the espresso-making process are the compression and surface characteristics of the coffee grounds prior to the introduction of hot water.
The compression of the coffee grounds in the basket of the portafilter is known as tamping, and may be performed using a variety of devices known in the art, which are generally referred to as espresso tampers. Types of espresso tampers known in the art include handheld manual tampers, fixed tamping surfaces typically mounted on coffee grinding machines, and large tamping machines which typically exert tamping force by means of a lever actuated or mechanized plunger.
Handheld manual tampers are generally solid ornamental objects configured with a lower surface adapted to allow the application of pressure on the coffee grounds in the filter basket, and an upper or outer surface suitable for holding in the hand of the user. Following compression of the grounds, the handheld tamper is typically spun on the surface of the compressed grounds, in order to form a smooth polished surface through which the heated water will be expressed in order to deliver the espresso coffee. Tamping surfaces typically attached to some types of coffee grinding machines are also known in the art. The portafilter is typically held against the underside of the fixed tamping surface such that the coffee grounds may be compressed by the application of upward force exerted manually by the user. The ability of such manually operated-tampers known in the art to deliver a precise predetermined degree of compression of the grounds is limited, as the magnitude of the tamping force applied is determined solely by the tactile judgment of the user. It is therefore very difficult for even a skilled user to obtain precise and repeatable application of any predetermined optimum tamping force using a manual tamper of the types known in the art.
Tamping machines operate by the mechanical application of tamping force to compress the coffee grounds, wherein the tamping force may be generated using a hand lever operated, or otherwise mechanically powered plunger which compresses the grounds in a portafilter basket. Tamping machines of the types known in the art may be controlled to deliver a relatively precise tamping force through the use of complex force measurement mechanisms. However, tamping machines are limited in their use due to their large size and expense, and the fact that they must generally be permanently mounted in a single location, which can be inconvenient for the user. Further, tamping machines known in the art do not allow for the desirable polishing of the surface of the compressed coffee grounds by spinning of the tamper surface, or for desirable tactile feedback to the user regarding the uniformity or lack thereof of the tamping process.
It is an object of the present invention to provide a handheld espresso tamper to overcome some of the limitations of the espresso tampers of the prior art. A further object of the handheld espresso tamper according to the present invention is to enable accurate repeatability of the tamping compressive force applied through the inventive handheld tamper. Additional advantages of several embodiments of the handheld espresso tamper according to the present invention include the ease with which the repeatable tamping force may be applied by a user, the variability of the tamping force applied for use with different espresso applications or equipment, and the safety, comfort, effectiveness and efficiency of use of the handheld espresso tamper by the user.